// (C) Copyright Jonathan Turkanis 2005.

// Distributed under the Boost Software License, Version 1.0. (See accompanying

// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt.)

// See http://www.boost.org/libs/iostreams for documentation.

// Note: bidirectional streams are not supported.

#ifndef BOOST_IOSTREAMS_COMPOSE_HPP_INCLUDED

#define BOOST_IOSTREAMS_COMPOSE_HPP_INCLUDED

#if defined(_MSC_VER) && (_MSC_VER >= 1020)

# pragma once

#endif

#include <algorithm>          // min.

#include <utility>            // pair.

#include <boost/config.hpp>   // DEDUCED_TYPENAME.

#include <boost/iostreams/categories.hpp>

#include <boost/iostreams/detail/adapter/direct_adapter.hpp>

#include <boost/iostreams/detail/call_traits.hpp>

#include <boost/iostreams/detail/closer.hpp>

#include <boost/iostreams/detail/enable_if_stream.hpp>

#include <boost/iostreams/operations.hpp>

#include <boost/iostreams/traits.hpp>      // mode_of, is_direct.

#include <boost/mpl/if.hpp>

#include <boost/ref.hpp>

#include <boost/static_assert.hpp>

#include <boost/type_traits/is_convertible.hpp>

namespace boost { namespace iostreams {

namespace detail {

template<typename Filter, typename Device>

struct composite_mode {

    typedef typename mode_of<Filter>::type           filter_mode;

    typedef typename mode_of<Device>::type           device_mode;

    typedef is_convertible<filter_mode, dual_use>    is_dual_use;

    typedef typename

            mpl::if_<

                is_convertible<device_mode, input>,

                input,

                output

            >::type                                  type;

};

//

// Template name: composite_device.

// Description: Provides a Device view of a Filter, Device pair.

// Template paramters:

//      Filter - A model of Filter.

//      Device - An indirect model of Device.

//

template< typename Filter,

          typename Device,

          typename Mode =

              BOOST_DEDUCED_TYPENAME composite_mode<Filter, Device>::type >

class composite_device {

private:

    typedef typename detail::param_type<Device>::type       param_type;

    typedef typename

            iostreams::select<  // Disambiguation for Tru64.

                is_direct<Device>,  direct_adapter<Device>,

                is_std_io<Device>,  Device&,

                else_,              Device

            >::type                                         value_type;

public:

    typedef typename char_type_of<Filter>::type             char_type;

    struct category

        : Mode,

          device_tag,

          closable_tag,

          flushable_tag,

          localizable_tag,

          optimally_buffered_tag

        { };

    composite_device(const Filter& flt, param_type dev);

    std::streamsize read(char_type* s, std::streamsize n);

    std::streamsize write(const char_type* s, std::streamsize n);

    stream_offset seek( stream_offset off, BOOST_IOS::seekdir way,

                        BOOST_IOS::openmode which =

                            BOOST_IOS::in | BOOST_IOS::out );

    void close();

    void close(BOOST_IOS::openmode which);

    bool flush();

    std::streamsize optimal_buffer_size() const;

    template<typename Locale> // Avoid dependency on <locale>

    void imbue(const Locale& loc)

    {

        iostreams::imbue(filter_, loc);

        iostreams::imbue(device_, loc);

    }

    Filter& first() { return filter_; }

    Device& second() { return device_; }

private:

    Filter      filter_;

    value_type  device_;

};

//

// Template name: composite_device.

// Description: Provides a Device view of a Filter, Device pair.

// Template paramters:

//      Filter - A model of Filter.

//      Device - An indirect model of Device.

//

template<typename Filter1, typename Filter2>

class composite_filter {

private:

     typedef reference_wrapper<Filter2>           filter_ref;

public:

    typedef typename char_type_of<Filter1>::type  char_type;

    struct category

        : mode_of<Filter1>::type,

          filter_tag,

          multichar_tag,

          closable_tag,

          flushable_tag,

          localizable_tag,

          optimally_buffered_tag

        { };

    composite_filter(const Filter1& filter1, const Filter2& filter2)

        : filter1_(filter1), filter2_(filter2)

        { }

    template<typename Source>

    std::streamsize read(Source& src, char_type* s, std::streamsize n)

    {

        composite_device<filter_ref, Source> cmp(boost::ref(filter2_), src);

        return iostreams::read(filter1_, cmp, s, n);

    }

    template<typename Sink>

    std::streamsize write(Sink& snk, const char_type* s, std::streamsize n)

    {

        composite_device<filter_ref, Sink> cmp(boost::ref(filter2_), snk);

        return iostreams::write(filter1_, cmp, s, n);

    }

    template<typename Device>

    stream_offset seek( Device& dev, stream_offset off, BOOST_IOS::seekdir way,

                        BOOST_IOS::openmode which =

                            BOOST_IOS::in | BOOST_IOS::out )

    {

        composite_device<filter_ref, Device> cmp(boost::ref(filter2_), dev);

        return iostreams::seek(filter1_, cmp, off, way, which);

    }

    template<typename Device>

    void close( Device& dev,

                BOOST_IOS::openmode which =

                    BOOST_IOS::in | BOOST_IOS::out )

    {

        composite_device<filter_ref, Device> cmp(boost::ref(filter2_), dev);

        iostreams::close(filter1_, cmp, which);

    }

    template<typename Device>

    bool flush(Device& dev)

    {

        composite_device<Filter2, Device> cmp(filter2_, dev);

        return iostreams::flush(filter1_, cmp);

    }

    std::streamsize optimal_buffer_size() const

    {

        std::streamsize first = iostreams::optimal_buffer_size(filter1_);

        std::streamsize second = iostreams::optimal_buffer_size(filter2_);

        return first < second ? second : first;

    }

    template<typename Locale> // Avoid dependency on <locale>

    void imbue(const Locale& loc)

    {   // To do: consider using RAII.

        iostreams::imbue(filter1_, loc);

        iostreams::imbue(filter2_, loc);

    }

    Filter1& first() { return filter1_; }

    Filter2& second() { return filter2_; }

private:

    Filter1  filter1_;

    Filter2  filter2_;

};

template<typename Filter, typename FilterOrDevice>

struct composite_traits

    : mpl::if_<

          is_device<FilterOrDevice>,

          composite_device<Filter, FilterOrDevice>,

          composite_filter<Filter, FilterOrDevice>

      >

    { };

} // End namespace detail.

template<typename Filter, typename FilterOrDevice>

struct composite : detail::composite_traits<Filter, FilterOrDevice>::type {

    typedef typename detail::param_type<FilterOrDevice>::type param_type;

    typedef typename detail::composite_traits<Filter, FilterOrDevice>::type base;

    composite(const Filter& flt, param_type dev)

        : base(flt, dev)

        { }

};

//--------------Implementation of compose-------------------------------------//

// Note: The following workarounds are patterned after resolve.hpp. It has not

// yet been confirmed that they are necessary.

#ifndef BOOST_IOSTREAMS_BROKEN_OVERLOAD_RESOLUTION //-------------------------//

# ifndef BOOST_IOSTREAMS_NO_STREAM_TEMPLATES //-------------------------------//

template<typename Filter, typename FilterOrDevice>

composite<Filter, FilterOrDevice>

compose( const Filter& filter, const FilterOrDevice& fod

         BOOST_IOSTREAMS_DISABLE_IF_STREAM(FilterOrDevice) )

{ return composite<Filter, FilterOrDevice>(filter, fod); }

template<typename Filter, typename Ch, typename Tr>

composite< Filter, std::basic_streambuf<Ch, Tr> >

compose(const Filter& filter, std::basic_streambuf<Ch, Tr>& sb)

{ return composite< Filter, std::basic_streambuf<Ch, Tr> >(filter, sb); }

template<typename Filter, typename Ch, typename Tr>

composite< Filter, std::basic_istream<Ch, Tr> >

compose(const Filter& filter, std::basic_istream<Ch, Tr>& is)

{ return composite< Filter, std::basic_istream<Ch, Tr> >(filter, is); }

template<typename Filter, typename Ch, typename Tr>

composite< Filter, std::basic_ostream<Ch, Tr> >

compose(const Filter& filter, std::basic_ostream<Ch, Tr>& os)

{ return composite< Filter, std::basic_ostream<Ch, Tr> >(filter, os); }

template<typename Filter, typename Ch, typename Tr>

composite< Filter, std::basic_iostream<Ch, Tr> >

compose(const Filter& filter, std::basic_iostream<Ch, Tr>& io)

{ return composite< Filter, std::basic_iostream<Ch, Tr> >(filter, io); }

# else // # ifndef BOOST_IOSTREAMS_NO_STREAM_TEMPLATES //---------------------//

template<typename Filter, typename FilterOrDevice>

composite<Filter, FilterOrDevice>

compose( const Filter& filter, const FilterOrDevice& fod

         BOOST_IOSTREAMS_DISABLE_IF_STREAM(FilterOrDevice) )

{ return composite<Filter, FilterOrDevice>(filter, fod); }

template<typename Filter>

composite<Filter, std::streambuf>

compose(const Filter& filter, std::streambuf& sb)

{ return composite<Filter, std::streambuf>(filter, sb); }

template<typename Filter>

composite<Filter, std::istream>

compose(const Filter& filter, std::istream& is)

{ return composite<Filter, std::istream>(filter, is); }

template<typename Filter>

composite<Filter, std::ostream>

compose(const Filter& filter, std::ostream& os)

{ return composite<Filter, std::ostream>(filter, os); }

template<typename Filter>

composite<Filter, std::iostream>

compose(const Filter& filter, std::iostream& io)

{ return composite<Filter, std::iostream>(filter, io); }

# endif // # ifndef BOOST_IOSTREAMS_NO_STREAM_TEMPLATES //--------------------//

#else // #ifndef BOOST_IOSTREAMS_BROKEN_OVERLOAD_RESOLUTION //----------------//

template<typename Filter, typename Stream>

composite<Filter, Stream>

compose(const Filter& flt, const Stream& strm, mpl::true_)

{   // Bad overload resolution.

    return composite<Filter, Stream>(flt, const_cast<Stream&>(strm));

}

template<typename Filter, typename FilterOrDevice>

composite<Filter, FilterOrDevice>

compose(const Filter& flt, const FilterOrDevice& fod, mpl::false_)

{ return composite<Filter, FilterOrDevice>(flt, fod); }

template<typename Filter, typename FilterOrDevice>

composite<Filter, FilterOrDevice>

compose( const Filter& flt, const FilterOrDevice& fod

         BOOST_IOSTREAMS_DISABLE_IF_STREAM(T) )

{ return compose(flt, fod, is_std_io<FilterOrDevice>()); }

# if !BOOST_WORKAROUND(__BORLANDC__, < 0x600) && \

     !BOOST_WORKAROUND(BOOST_MSVC, <= 1300) && \

     !defined(__GNUC__) // ---------------------------------------------------//

template<typename Filter, typename FilterOrDevice>

composite<Filter, FilterOrDevice>

compose (const Filter& filter, FilterOrDevice& fod)

{ return composite<Filter, FilterOrDevice>(filter, fod); }

# endif // Borland 5.x, VC6-7.0 or GCC 2.9x //--------------------------------//

#endif // #ifndef BOOST_IOSTREAMS_BROKEN_OVERLOAD_RESOLUTION //---------------//

//----------------------------------------------------------------------------//

namespace detail {

//--------------Implementation of composite_device---------------------------//

template<typename Filter, typename Device, typename Mode>

composite_device<Filter, Device, Mode>::composite_device

    (const Filter& flt, param_type dev)

    : filter_(flt), device_(dev)

    { }

template<typename Filter, typename Device, typename Mode>

inline std::streamsize composite_device<Filter, Device, Mode>::read

    (char_type* s, std::streamsize n)

{ return iostreams::read(filter_, device_, s, n); }

template<typename Filter, typename Device, typename Mode>

inline std::streamsize composite_device<Filter, Device, Mode>::write

    (const char_type* s, std::streamsize n)

{ return iostreams::write(filter_, device_, s, n); }

template<typename Filter, typename Device, typename Mode>

stream_offset composite_device<Filter, Device, Mode>::seek

    (stream_offset off, BOOST_IOS::seekdir way, BOOST_IOS::openmode which)

{ return iostreams::seek(filter_, device_, off, way, which); }

template<typename Filter, typename Device, typename Mode>

void composite_device<Filter, Device, Mode>::close()

{

    typedef typename mode_of<Device>::type device_mode;

    BOOST_IOS::openmode which =

        is_convertible<device_mode, input>() ?

            BOOST_IOS::in :

            BOOST_IOS::out;

    close(which);

}

template<typename Filter, typename Device, typename Mode>

void composite_device<Filter, Device, Mode>::close(BOOST_IOS::openmode which)

{

    bool                                 nothrow = false;

    external_closer<value_type>          close_device(device_, which, nothrow);

    external_closer<Filter, value_type>  close_filter(filter_, device_, which, nothrow);

}

template<typename Filter, typename Device, typename Mode>

bool composite_device<Filter, Device, Mode>::flush()

{   // To do: consider using RAII.

    bool r1 = iostreams::flush(filter_, device_);

    bool r2 = iostreams::flush(device_);

    return r1 && r2;

}

template<typename Filter, typename Device, typename Mode>

std::streamsize

composite_device<Filter, Device, Mode>::optimal_buffer_size() const

{ return iostreams::optimal_buffer_size(device_); }

} // End namespace detail.

} } // End namespaces iostreams, boost.

#endif // #ifndef BOOST_IOSTREAMS_COMPOSE_HPP_INCLUDED